U.S. patent application number 13/752059 was filed with the patent office on 2014-07-31 for shear and seal system for subsea applications.
This patent application is currently assigned to SCHLUMBERGER TECHNOLOGY CORPORATION. The applicant listed for this patent is SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Oguzhan Guven.
Application Number | 20140209314 13/752059 |
Document ID | / |
Family ID | 51221686 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140209314 |
Kind Code |
A1 |
Guven; Oguzhan |
July 31, 2014 |
SHEAR AND SEAL SYSTEM FOR SUBSEA APPLICATIONS
Abstract
A system and methodology facilitates utilization of a valve and
a cutter both of which may be used in a subsea test tree. The valve
comprises a ball element pivotably mounted in a housing and having
an exterior surface and a passageway sized to receive a conveyance
therethrough. The cutter also is located in the housing but at a
position spaced from the ball element. The cutter is oriented for
selective severing of the conveyance. Additionally, a seal system
is positioned to act against a surface of the ball element.
Inventors: |
Guven; Oguzhan; (Bellaire,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHLUMBERGER TECHNOLOGY CORPORATION |
Sugar Land |
TX |
US |
|
|
Assignee: |
SCHLUMBERGER TECHNOLOGY
CORPORATION
Sugar Land
TX
|
Family ID: |
51221686 |
Appl. No.: |
13/752059 |
Filed: |
January 28, 2013 |
Current U.S.
Class: |
166/336 ;
166/316 |
Current CPC
Class: |
E21B 2200/04 20200501;
E21B 33/064 20130101; E21B 34/045 20130101; E21B 33/063
20130101 |
Class at
Publication: |
166/336 ;
166/316 |
International
Class: |
E21B 34/04 20060101
E21B034/04; E21B 34/06 20060101 E21B034/06 |
Claims
1. A system for use in a subsea test tree, comprising: a subsea
test tree housing having a passageway sized to receive a conveyance
therethrough; a cutter mounted along the passageway, the cutter
comprising a plurality of cutter blades selectively movable into
the passageway by a plurality of pistons at a shear location; a
valve mounted along the passageway separate from the cutter, the
valve being a ball valve having a ball with a ball passage sized to
receive the conveyance therethrough; and a seal member positioned
to seal against an outer surface of the ball when the ball is
pivoted to a position closing off flow along the passageway, the
distance between the seal and the shear location being less than 10
inches (25.4 cm).
2. The system as recited in claim 1, wherein the ball comprises a
relief area positioned to allow the ball to start closing before
the conveyance is pulled clear of the ball passage.
3. The system as recited in claim 2, wherein the ball has a rounded
leading edge at the ball passage and the ball is biased with a low
biasing force against the conveyance, the low force of the bias,
the relief area, and the rounded leading edge cooperating to
enhance the strip through capability of the valve.
4. The system as recited in claim 1, wherein the ball valve is
actuated by rod pistons.
5. The system as recited in claim 1, wherein the seal member is
positioned in a floating seal retainer.
6. The system as recited in claim 1, wherein the seal member
comprises a plurality of seals located on opposite sides of the
ball.
7. The system as recited in claim 1, wherein the cutter and the
valve are mounted in a common housing.
8. The system as recited in claim 1, wherein the ball is biased
into engagement with the seal member.
9. The system as recited in claim 1, wherein the distance between
the seal and the shear location is less than 5 inches (12.7
cm).
10. The system as recited in claim 1, wherein the distance between
the seal and the shear location is less than 4 inches (10.2
cm).
11. A method of shutting in a well, comprising: positioning a valve
along a flow path through a subsea test tree; providing the valve
with a ball pivotable between open and closed positions with
respect to the flow path; locating a cutter along the flow path to
create a shear location for cutting of a conveyance positioned in
the flow path and through the ball; and arranging a seal member to
seal off the flow path by sealingly engaging the ball at a location
less than 10 inches (25.4 cm) from the shear location.
12. The method as recited in claim 11, wherein arranging comprises
arranging the seal member to engage the ball at a location less
than 5 inches (12.7 cm) from the shear location.
13. The method as recited in claim 11, wherein arranging comprises
arranging the seal member to engage the ball at a location less
than 4 inches (10.2 cm) from the shear location.
14. The method as recited in claim 11, further comprising cutting a
coiled tubing conveyance with the cutter and then pivoting the ball
prior to withdrawal of the coiled tubing from an internal passage
of the ball.
15. The method as recited in claim 11, further comprising cutting a
wireline conveyance with the cutter and then pivoting the ball
prior to withdrawal of the coiled tubing from an internal passage
of the ball.
16. The method as recited in claim 11, wherein locating the cutter
comprises providing piston mounted cutter blades oriented for
selective movement into the flow path.
17. The method as recited in claim 11, wherein arranging the seal
member comprises utilizing seals on opposite sides of the ball.
18. A system, comprising: a valve comprising: a ball valve element
rotatably mounted in a housing, the ball valve element having an
exterior surface and a passageway sized to receive a conveyance
therethrough; a cutter located in the housing at a position spaced
from the ball valve element and oriented for selective severing of
the conveyance; and a seal system positioned to act against a
surface of the ball valve element.
19. The system as recited in claim 18, wherein the cutter comprises
at least one blade mounted on at least one piston.
20. The system as recited in claim 18, wherein the ball valve
element is actuated by rod pistons.
Description
BACKGROUND
[0001] Hydrocarbon fluids such as oil and natural gas may be
obtained from subsea wells. Subsea test trees enable well testing
and well cleanup operations to be conducted on subsea wells from an
offshore floating rig. In the event the well is to be shut down,
the subsea test tree includes valves for shutting in the well and
for preventing discharge of the landing string contents into an
associated riser. Additionally, various clean up or well testing
operations may involve running a conveyance mechanism, such as a
wireline or coiled tubing, through the subsea test tree. The subsea
test tree also may comprise a mechanism for cutting and removing
these conveyance mechanisms and for providing a leak tight barrier
in the bore after cutting and removing the conveyance
mechanism.
SUMMARY
[0002] In general, the present disclosure provides a system and
method of utilizing a valve and a cutter both of which may be used
in a subsea test tree. The valve comprises a ball element pivotably
mounted in a housing and having an exterior surface and a
passageway sized to receive a conveyance therethrough. In many
applications, a ball element actuation mechanism may provide an
optimized force output between a lower limit that is sufficient to
close the valve and an upper limit that is low enough to
accommodate stripping of the conveyance through the valve without
pinching. Additionally, a seal system is positioned to act against
a surface of the ball element. The cutter also is located in the
housing but at a position close to but spaced from the ball
element. The cutter is oriented for selective severing of the
conveyance.
[0003] However, many modifications are possible without materially
departing from the teachings of this disclosure. Accordingly, such
modifications are intended to be included within the scope of this
disclosure as defined in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Certain embodiments of the disclosure will hereafter be
described with reference to the accompanying drawings, wherein like
reference numerals denote like elements. It should be understood,
however, that the accompanying figures illustrate the various
implementations described herein and are not meant to limit the
scope of various technologies described herein, and:
[0005] FIG. 1 is a schematic illustration of a subsea well system
having a subsea test tree with a cutting and sealing system
comprising a cutter and a valve separate from the cutter for
sealing off a flow-through passageway through the subsea test tree,
according to an embodiment of the disclosure;
[0006] FIG. 2 is a cross-sectional view of an example of a cutting
and sealing system having a valve separate from a cutter in a
common housing, according to an embodiment of the disclosure;
[0007] FIG. 3 is a cross-sectional view similar to that illustrated
in FIG. 2 but showing the cutter in an actuated or cutting
position, according to an embodiment of the disclosure;
[0008] FIG. 4 is a cross-sectional view similar to that illustrated
in FIG. 3 but showing the valve actuated to a closed and sealed
position, according to an embodiment of the disclosure;
[0009] FIG. 5 is a partial cutaway view of the valve in the form of
a ball valve having a rotatable ball element, according to an
embodiment of the disclosure; and
[0010] FIG. 6 is a cross-sectional view of another example of the
cutting and sealing system, according to another embodiment of the
disclosure.
DETAILED DESCRIPTION
[0011] In the following description, numerous details are set forth
to provide an understanding of some embodiments of the present
disclosure. However, it will be understood by those of ordinary
skill in the art that the system and/or methodology may be
practiced without these details and that numerous variations or
modifications from the described embodiments may be possible.
[0012] The present disclosure generally involves a system and
methodology utilizing a cutting and sealing system having a valve
and a cutter. The cutting and sealing system may be used in a
subsea test tree. In an embodiment described in greater detail
below, the valve comprises a ball valve having a ball element
pivotably mounted in a housing which also serves as a housing
containing the cutter at a separate location. In many applications,
a ball element actuation mechanism applies a biasing force to the
ball element such that the force output is optimized between a
lower limit sufficient to close a valve and an upper limit that is
low enough to accommodate stripping of the conveyance through the
valve without pinching. Additionally, a seal system may be
positioned to act against a surface of the ball element. Other
types of valve elements also may be employed in some applications.
The ball or ball element has an exterior surface and a ball passage
sized to receive a conveyance therethrough. The cutter is oriented
for selective severing of the conveyance at a position separate
from but very close to the location at which a seal system seals
against an exterior surface of the ball element. This arrangement
enables cutting of the conveyance independently of the sealing
function while also allowing a rapid sealing off of the
flow-through passageway upon severing of the conveyance.
[0013] The valve element may be actuated between an open position
and a closed position blocking the passageway. If the valve element
comprises a ball, the ball is pivoted between an open position,
which allows flow of fluid through the internal ball passage and
along the overall flow-through passageway, and a closed position,
which blocks flow of fluid along the overall flow-through
passageway. In some applications, the ball element may comprise a
relief area which is positioned to allow the ball to begin closing
before the conveyance is pulled clear of the ball passage upon
severing of the conveyance. The relief area facilitates rapid
closing of the overall flow-through passage once the conveyance is
cut.
[0014] Depending on the application, the cutter also may comprise a
variety of components and configurations. For example, the cutter
may comprise a plurality of cutting elements, e.g. blades, mounted
on radial actuators. The radial actuators may be in the form of
pistons, e.g. hydraulic pistons, or other actuators that may
include other types of hydraulic actuators, electromechanical
actuators, or other suitable actuators having sufficient power to
cut through the conveyance. In a specific example, the cutting
elements comprise blades which are mounted to hydraulically
actuated pistons powered by a suitable hydraulic actuating fluid
which may be delivered through a variety of control lines, ports,
and/or other passageways. The hydraulically actuated pistons are
mounted radially in a surrounding housing to enable controlled
movement of the cutting blades in a radially inward direction to
selectively sever the conveyance. By way of example, the system may
utilize a pair of hydraulically actuated pistons or other types of
actuators, although the system may be designed to accommodate
additional cutting blades/actuators or an individual cutting blade
and actuator.
[0015] In a subsea test tree application, a subsea test tree is
employed to enable well testing and well cleanup operations to be
conducted from, for example, an offshore floating rig. The cutting
and sealing system is combined into the subsea test tree
installation and may be employed to reliably and repeatedly cut
conveyances, e.g. coiled tubing, wireline, or other conveyances,
and to provide a gas tight seal after severing of the conveyance.
In embodiments described herein, the cutting and sealing system
utilizes a cutter ram and a strip through ball valve although
various other components and component configurations may be used
in forming the cutting and sealing system.
[0016] The cutting and sealing system provides a fast acting and
reliable system to shut-in the well with two barriers and to
prevent discharge of the landing string contents into the riser.
The cutting and sealing system also provides a fast acting and
reliable system for disconnecting the landing string from the test
string in well testing and well cleanup operations. In operation,
the cutting and sealing system of the subsea test tree initially
cuts and removes the conveyance medium (e.g. coiled tubing,
slickline, or wireline) that may be present, and then provides a
gas tight barrier/seal in the wellbore before disconnecting. This
dual functionality is achieved by the cutting and sealing system
installed as part of the subsea test tree.
[0017] Referring generally to FIG. 1, an embodiment of a system,
e.g. a subsea well system, is illustrated as comprising a cutting
and sealing system designed to shear a conveyance and to seal off a
passageway. In this example, the cutting and sealing system is
employed in a subsea test tree, but the cutting and sealing system
also may be employed in other types of subsea or surface well
equipment. The valve may be designed to accommodate passage of many
types of conveyances, including coil tubing conveyances, wireline
conveyances, slickline conveyances, and other suitable conveyances,
as such conveyances are moved along the overall flow-through
passageway within the subsea well system. It should further be
noted the cutting and sealing system may be used in combination
with other types of equipment in both well and non-well related
applications.
[0018] In the example of FIG. 1, a subsea well system 20 is
illustrated as comprising a surface structure 22, e.g. a floating
rig, positioned at the sea surface 24. The surface structure 22 may
be coupled with a subsea test tree 26, located at a seafloor 28, by
a riser 30. The subsea test tree 26 is disposed above a well 32
which may comprise at least one wellbore 34. In the example
illustrated, a cutting and sealing system 36 is mounted in the
subsea test tree 26 and comprises a valve 38, such as a ball valve
having a ball element 40 which is pivotable and may be actuated to
an open position allowing access through a subsea test tree
passageway 42 or to a closed position blocking access through
passageway 42. The ball element may be pivotably mounted to a
supporting housing 44 which surrounds the ball element 40 and may
be part of the subsea test tree 26. In some applications, the
housing 44 and the cutting and sealing system 36 may be designed as
a modular system for selective connection into the subsea test tree
26 or into other suitable equipment.
[0019] The cutting and sealing system 36 also comprises a cutter 46
which may be mounted in the supporting housing 44. In this type of
embodiment, the housing 44 serves as a common housing for both the
ball valve 38 and the cutter 46. For example, the housing 44 may be
a unitary structure which supports both the valve 38 and the cutter
46 at separate locations but in close proximity to each other along
the overall subsea test tree passageway 42.
[0020] Depending on the subsea application, a conveyance 48 may be
used to convey tools and/or other equipment down through riser 30
and subsea test tree 26. The passageway 42 is sized to accommodate
passage of the tools, equipment and conveyance 48 down into
wellbore 34. Upon the occurrence of certain events, the passageway
42 may be rapidly closed to shut in the well 32 by actuating cutter
46 to sever the conveyance 48 while also actuating valve 38 to
shift ball element 40 to a closed, sealed position. The ball
element 40 is designed to automatically form a gas tight seal upon
pivoting to a closed position. Depending on the design of valve 36
and on the environment in which it is employed, a variety of
actuators 50 may be used to actuate ball element 40 between open
and closed positions. By way of example, actuators 50 may comprise
hydraulic actuators, e.g. rod pistons, other hydraulic actuators,
electrical actuators, e.g. solenoids, electromechanical actuators,
or other suitable actuators designed to rotate the ball 40 between
open and closed positions.
[0021] Referring generally to FIG. 2, an embodiment of cutting and
sealing system 36 is illustrated. In this embodiment, cutter 46
comprises a shear ram type cutter and valve 38 comprises a strip
through ball valve. The cutter 46 and ball valve 38 are packaged
together in housing 44 which, in this example, is a unitary housing
structure 52. For example, unitary housing structure 52 may
comprise a single piece housing structure into which both ball
valve 38 and cutter 46 are mounted. The housing 52 may be a modular
type housing selectively mounted in subsea test tree 26, or the
housing 52 may be part of subsea test tree 26.
[0022] In the illustrated example, cutter 46 is designed with
capabilities for cutting several types of subsea intervention
media, e.g. coiled tubing, wireline, slickline, braided line, or
other types of conveyances. The cutter 46 comprises at least one
actuator 54 coupled with a cutter blade 56 and oriented for
selective movement into passageway 42 when conveyance 48 is to be
severed. In the specific embodiment illustrated, cutter 46
comprises a plurality of actuators 54, e.g. two actuators, coupled
with a plurality of corresponding cutter blades 56. The actuators
54 are mounted in housing 52 and oriented in a radial direction
such that the cutter blades 56 move radially into and out of
passageway 42.
[0023] Depending on the application, a variety of actuators 54 may
be employed, including hydraulic actuators, electromechanical
actuators, and other suitable actuators. In the example
illustrated, the actuators 54 are hydraulic actuators and each
actuator 54 utilizes a piston 58 slidably mounted in a
corresponding cylinder 60. The pistons 58 may be actuated or moved
along corresponding cylinders 60 by hydraulic fluid introduced
through and/or discharged through appropriate hydraulic ports 62.
The cylinders 60 and pistons 58 may be mounted in housing 52 by an
appropriate coupling structure 64 and oriented in a radial
direction, as illustrated.
[0024] In the embodiment illustrated, valve 38 is a ball valve
having ball 40 pivotably mounted within housing 52 and biased into
sealing engagement with a seal 66. By way of example, the seal 66
may be mounted in a floating seal retainer 68 captured in a
corresponding recess 70 formed within housing 52. The ball 40 may
be biased against seal 66 by an appropriate spring biased
structure. For example, an actuating ring 72 may be engaged with
ball 40 and biased by a spring 74 positioned between the actuating
ring 72 and a support structure 76 located within or forming part
of housing 52. As described in greater detail below, the actuating
ring 72 may be designed to induce pivoting motion of ball 40 as
ball 40 is transitioned between open and closed positions.
[0025] Ball valve 30 and ball element 40 may have a variety of
configurations designed to selectively enable or block flow of
fluid along the overall through passageway 42. For example, ball 40
comprises an internal ball passage 78 sized to accommodate fluid
flow and to allow movement of conveyance 48 therethrough. The ball
40 also may comprise a relief area 80 positioned to allow the ball
40 to start closing before the conveyance 48 is pulled clear of the
ball passage 78. Additionally, ball element 40 may comprise a
rounded edge or edges 82, e.g. rounded lead edges, to further
promote strip through capability with respect to severing and
removing conveyance 48. For example, the lead edge 82 along the
circumference of ball passage 78 closest to cutter 46 may be
rounded to facilitate strip through.
[0026] In the example illustrated, the ball valve 38 and cutter 46
are positioned in close proximity to each other within housing 52.
For example, ball valve 38 may be assembled in housing 52 in a
manner so the distance between the seal location and the shear
location is minimized. The seal location is created by seal 66
acting against an exterior surface 84 of ball 40, and the shear
location is the location at which cutter blades 56 move to engage
conveyance 48 when cutting through and shearing the conveyance. In
FIG. 2, the distance between the seal location and the shear
location is labeled by reference numeral 85 and in many
applications is less than 10 inches (25.4 cm). However, some
applications are designed to utilize very rapid sealing off of the
passageway 42 upon severing of the conveyance 48, and the distance
is less than 5 inches (12.7 cm). Some embodiments utilize a
distance 85 of less than 4 inches (10.2 cm) which, along with the
use of relief area 80, enables extremely rapid sealing following
cutting of the conveyance 48 even though cutter 46 and ball valve
38 are separated and operated at unique locations along passageway
42. This type of packaging provides a very short distance between
the shear and seal planes and allows the sheared medium, e.g.
conveyance 48, to be cleared from the ball passage 78 very quickly
when the ball valve 38 closes.
[0027] In a shearing and sealing operation, hydraulic fluid is
delivered to actuators 54 and into cylinders 60 via the appropriate
ports 62. The pressure of the hydraulic fluid drives the pistons 58
in a radially inward direction, as illustrated in FIG. 3. The
radially inward movement of pistons 58 drives cutter blades 56 into
and through conveyance 48, e.g. coil tubing, wireline, or
slickline, until the conveyance is severed at the shear
location.
[0028] Once the conveyance 48 is sheared, the portion of conveyance
48 on the ball valve side of actuators 54 may be withdrawn and
pulled out of ball 40 along ball passage 78. The ball 40 is then
pivoted to a closed position which blocks flow of fluid along
passageway 42, as illustrated in FIG. 4. Use of relief area 80
allows initiation of the pivoting of ball 40 to the closed position
prior to full removal of the conveyance 48 from ball passage 78.
Even if the conveyance 48 does not fully clear the ball valve 38,
the optimized, e.g. low, closing force exerted by actuator 50
prevents pinching of the conveyance 48 and facilitates strip
through of the conveyance. Other characteristics which facilitate
strip through capability of the ball valve 38 comprise the use of
relief area 80 and/or the use of rounded edges 82, such as the
rounded lead edge. The low biasing force, the relief area, and the
rounded edges cooperate to lower the risk of pinching and
facilitate the strip through capability of the valve.
[0029] Ball 40 may be pivoted between open and closed positions by
a variety of mechanisms, however the illustrated example utilizes a
ball operator in the form of actuating ring 72. As actuating ring
72 is shifted from a first position, as illustrated in FIG. 3, to a
second position, as illustrated in FIG. 4, the actuating ring 72
causes pivoting motion of ball 40 between positions, e.g. between
open and closed positions. In the example illustrated, actuating
ring 72 comprises engagement features 86 which are coupled with
corresponding engagement features 88 on ball 40, as illustrated in
FIG. 5. For example, engagement features 86 may comprise nubs or
other extensions and corresponding engagement features 88 may
comprise slots designed to receive engagement features 86.
[0030] As the actuating ring 72 is transitioned linearly between
positions, the engagement features 86 are moved along corresponding
engagement features 88 in such a manner that ball 40 is forced to
selectively pivot between open and closed positions. Movement of
actuating ring 72 (or other ball operator) may be selectively
caused by suitable ball actuators 50. In a specific example, ball
actuators 50 comprise rod pistons 90 which may be selectively
operated to move actuating ring 72 between positions. The rod
pistons 90 may be hydraulically actuated and are designed to
provide sufficient force to rotate ball 40 without having too high
of a force that could otherwise cause the sheared medium 48, e.g.
conveyance, to be pinched. This facilitates stripping of the medium
48 through the ball valve 38. It should be noted that ball 40 may
be designed with generous radii on the ball valve edges, e.g. lead
edge 82, to facilitate the strip through process and the closing
off of passageway 42.
[0031] Referring generally to FIG. 6, another embodiment of cutting
and sealing system 36 is illustrated. In this embodiment, many of
the features are similar to features illustrated and described in
FIGS. 2-5 and those features have been labeled with common
reference numerals. However, the embodiment illustrated in FIG. 6
employs a different method of sealing the ball valve 38. In this
example, the ball 40 floats and is captured between a plurality of
seals 92 in which at least one seal 92 is located on each opposing
side of ball 40. For example, at least one seal 92 may be
positioned between housing 52 and ball 40 on the side of ball 40
closest to cutter 46 and at least one seal 92 may be positioned on
an opposite side of the ball 40 between support structure 76 and
ball 40.
[0032] When the ball valve 30 is transitioned to a closed position,
as illustrated in FIG. 6, the ball 40 is sealed against the seal or
seals 92 on one side of the ball depending on the direction of
pressure acting against the ball 40. In this example, the ball
valve 38 similarly functions as a strip through ball valve and may
utilize rounded edges 82. In the embodiment illustrated, however,
the ball 40 is constructed without relief area 80 to facilitate
sealing on either side of the ball 40. Thus, the medium/conveyance
48 is stripped through the entire ball 40 and ball passage 78 prior
to shifting the ball 40 to the closed position.
[0033] The cutting and sealing system 36 may have a variety of
configurations for use in subsea applications and other
applications. Additionally, the components and materials used in
constructing the valve 38 and/or cutter 46 may vary from one
application to another depending on operational and environmental
parameters. The cutting and sealing functions may be performed by a
variety of individual or plural cutting blades and seals,
respectively. Similarly, the valve actuation mechanisms may rely on
hydraulic systems powered via control lines, wellbore pressures,
pressure storage devices, or other suitable pressure sources. The
valve actuation mechanisms and cutter actuation mechanisms also may
utilize electrical actuators, electromechanical actuators,
combinations of actuators, and other suitable mechanisms for
achieving the desired actuation. Cutter blades and cutting edges
also may be designed from a variety of components and/or materials
which may be selected based on the environment and/or materials to
be cut.
[0034] Although a few embodiments of the disclosure have been
described in detail above, those of ordinary skill in the art will
readily appreciate that many modifications are possible without
materially departing from the teachings of this disclosure.
Accordingly, such modifications are intended to be included within
the scope of this disclosure as defined in the claims.
* * * * *